


Don't take advantage of me

by wisteriapillar



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alternate Universe - Modern Setting, Alternate Universe - Sugar Daddy, Anal Fingering, Anal Sex, Christmas Fluff, Discord: The Kingdom of Shipping (Dr. STONE), Established Relationship, Gay Sex, Gift Exchange, Implied/Referenced Character Death, M/M, Marriage Proposal, TKSevents, TheKingdomofShipping
Language: English
Status: Completed
Published: 2020-12-26
Updated: 2020-12-26
Packaged: 2021-03-11 05:08:10
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 5,118
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28329489
Author URL: https://archiveofourown.org/users/wisteriapillar/pseuds/wisteriapillar
Summary: Ryusui and Senku in the modern world- Sugar daddy au with much fluff and marriage proposals.
Relationships: Ishigami Senkuu/Nanami Ryuusui
Comments: 3
Kudos: 42
Collections: 2020 TKS Secret Santa





	Don't take advantage of me

**Author's Note:**

  * For [WinglessCookie](https://archiveofourown.org/users/WinglessCookie/gifts).



Christmas lights hung from every store, every lamp post, it seemed no matter where he went, Senku couldn't keep himself away from the constant reminders of the holiday quickly approaching.

Not that it was something new, it came around every year, so what made this time so different?

_ "My darling, what do you think about having a proper Christmas together?"  _ The feeling of Ryusui's soft lips kissing his knuckles flashed through the young scientist's mind.  _ "You're a proper adult, and I want to get you something that proves just how much I love you." _

"Gah, what's the big deal?" He shook off the needless anxiety, continuing his window shopping. They had agreed on one special gift for each other, something that had meaning. A true 'it's the thought that counts' sort of thing.

Him and Ryusui had been dating for a bit over a year now, and they weren't particularly a normal couple. Forget the fact that they were both men, he was 18 and that perverted sailor was 34. If society were to accept them for at least being gay, that was another hurdle they'd have to cross.

Senku's early years had been fine, with a loving adoptive father and endless opportunities to become enthralled with science and the ways of the world. Supporting his old man and his dream to become an astronaut until the very end. And disappointingly, that end had come far too soon for his liking.

A failed rocket landing, after being in space for so long, that damned system failed them and had all passengers on board killed. He would never forget the way his entire body froze watching that broadcast. Not only was his only family gone, the man who had inspired him… the man who made it possible for the boy to get as far as he did…gone.

Byakuya's extended family reached out, offering help and even a place to stay, but it would be giving up too much. At the very least, he needed to stay near his friends. The house was left to him, but paying the bills meant getting a job. School, studying, and a job at 16 wasn't unheard of, but it was slowly driving Senku to his breaking point. He refused to stop putting less effort into what he loved. It led to his health worsening, sleepless nights and common nosebleeds. Even though he  _ knew _ what he should be doing to prevent all of this, whenever he remembered his father, he just-...

The sudden squealing of a child snapped him out of his trance, blinking and shaking his head. It'd been a while since he really looked back to what happened back then. But he could never forget meeting Ryusui for the first time, even if he tried. His obnoxious tendencies made for a truly bombastic first impression, and he wasn't scared to express his desires to a 17 year old.

Senku laughed to himself, noticing the puff of air and pulled up his scarf, stopping in front of a jewelry store.

One of the first things he had noticed about his lover was his earrings, diamonds. Basically screaming for anyone to ask if they were real.

They were just in the same coffee shop, nothing special, a normal morning before work when their eyes had met. Naturally, he looked away, but he noticed that the other hadn't. Those striking amber eyes looking at him like no one else ever had.

When he asked for his number, he was shocked, to say the least. Someone as rich and successful as him wouldn't want anything to do with a poor kid like him unless he had ulterior motives.

Which was… sort of true. But Ryusui at least told him in person, preferring to look him in the eye. He warmed the younger up to the idea of being with him, kisses being a small starting point.

There was something alluring about the man, something that when he leaned in the first time and pressed their lips together, he didn't stop him. His old man would have a heart attack, knowing his first kiss was with a man well over a decade older than him.

_ "You know this is terribly illegal, right?" _

_ "I wouldn't have brought you here otherwise, little dove." _ Ryusui's voice had been low back then, completely serious about making the boy his own.

Senku's scarlet eyes glanced over to the mansion, the difference of status starting to really settle in. They've only been on a few dates, so not opening up about his financial situation wasn't abnormal, but he felt as if it might be awkward since he was going to find out sooner or later.

At the news of what had happened, he made sure to make it clear that pity wasn't what he was looking for.

But the sailor didn't skip a beat, grabbing his hands with a devilish grin, as if he were baring his fangs and alluring a mate.  _ "Of course not, don't you know what sort of relationship our types typically have?"  _

_ "I pay you to let me fuck you, not because I pity you." _

A shiver ran down his spine, recalling those words, even though anyone would be able to see through that excuse. As selfish as everyone saw him, he was stupidly kind. It was just easier for Senku if he imagined that he was being taken advantage of.

God, he remembered his first time with that man… He never considered sex to be that big of a deal, but Ryusui knew how to fuck a virgin stupid. The sort of stamina he displayed shouldn't be possible for a human, honestly.

But with the money he earned, he could pay all the bills and still have more than he knew what to do with. Pouring it into stocks and his own personal projects.

Once he had turned 18, the blonde properly asked him out, and they started dating. He's not sure how his friends would look at him, if they knew, but he didn't mind. In that year, if anything, he had learned that maybe romantic feelings weren't something he needed to throw away. 'Swept him off his feet' might not be too much of a metaphor in their scenario.

Now, a year later, and he could finally use his money for something nice. Repay Ryusui for all that he's done for him, when the only thing he felt he could do was offer his body.

But fuck, what do you get a man who has everything?

"Sir?"

A woman's voice came from the jewelry store's door, a confused look on her face. "Are you looking for something? You know we're here to help you, don't you? Don't be shy." She smiled, opening the door and Senku sighed, cursing himself for daydreaming as he made his way inside.

"Is there something in particular you're looking for?"

"... A gift. Uh- for a significant other." Well, that was obvious, wasn't it? The day before Christmas, what else was he gonna be looking for? "They're just... stupidly rich. It's hard to figure out what someone like that wants."

The woman seemed shocked for a second, but it soon turned into a smile, much more natural than the forced one she probably gave to every customer. "Ah, I see. So something even like a nice watch such as this wouldn't seem good enough to you…" She tapped her chin, looking like she was having fun with this. "You really love this person, right?"

Senku paused, looking to the side as he nodded. "Yeah, I guess you could say that." He could imagine Ryusui's face now, he'd be all over him after hearing something like that.

"Have you considered… couple's rings?"

Her eyes were basically sparkling, as much as he wanted to look at her as if she were crazy, the idea wasn't all that terrible. Not that he had ever thought about it, of course not, but he knew that his lover would never take off that damned ring, no matter the cost.

"Well, I wouldn't want anything too fancy, it hasn't been  _ that _ long…" What, he was acting coy now? "I don't think he's gonna be letting me go soon, so I may as well get them." He smirked, barely noticing that he let it slip that his significant other was a male. If anything, the employee seemed even more excited to help.

"That's so sweet!" She clapped her hands together, walking behind the counter and gesturing to the selection of rings. "Couple's rings are usually more simple, not as much of a commitment as engagement rings." 

"Uh… something plain? Like a silver band?" Senku looked over, inside the glass case was quite the selection. There were...a lot of silver bands. How was it possible that there were this many designs? "Something like this," He pointed to one that didn't stick out too much, nor was it clunky at all. Imagining Ryusui's face once he opened it, not expecting his reluctant little lover to get them something quite so binding.

"Yeah, I'll take that pair."

He spoke with a soft smile on his face, blaming the sudden memories of how the two met on his impulse buy. The price was a bit more than expected, but with all the money he'd been given, Senku didn't think twice as he handed the employee his credit card.

Being handed the bag and saying goodbye to the worker, though he probably wouldn't ever see her again, she might just have been the pushing point for him actually buying these. Who would have thought? Someone who insisted on pushing these sort of feelings aside would be the one to go out and cement their relationship as something serious.

Now after all that daydreaming, he could actually go and see that stupid man he had spent so much time thinking about. It was Christmas Eve, but… He was never one to follow traditions that closely.

He had a key to Ryusui's home, unlocking the door and kicking off the snow from his shoes before walking inside.

The first thing he heard was giggling from a voice that wasn't his lover's, putting the ring box in his back pocket, he hung his coat and peeked his head into the living room.

There he was, his blonde hair tied back into a low ponytail, holding a small figure up as they danced to your typical Christmas music. It was a young girl, looking to be about 10 years old.

Amber eyes moved over to meet his own, a big smile showing on the man's face. "Senku! I was wondering when you would come over." He turned the girl, her expression turning a bit shy. "I was hoping to introduce you to my lovely niece. Her name's Suika. Suika, this is Senku." He held out her small hand, her face turning red as he made her wave at him.

It was a shock, but he just laughed and stepped forward. No matter what he did, he could never get used to the surprises that came from being with him. His smile turned gentle and he walked over, holding out his hand, letting her choose if she were to take it or not.

Suika's eyes looked from her uncle's to Senku's, obviously a bit nervous but after a second, she reached out and shook his hand. "Nice to meet you… Suika will be of help however she can!" 

Ryusui laughed, setting her down and crossing his arms. "I've talked so much about you, she absolutely adores the science you study! Says she wants to become a helper of sorts!" 

The girl's face once again shot up in red, softly hitting his leg. "Uncle! You don't have to embarrass me!"

The younger male stood and watched in… he's not too sure what he was feeling. Bittersweet? He kneeled down, patting her head with a grin. "That's good, a scientist like me will always need a helper. I've been looking for an assistant, and I had a feeling one like you would pop up soon."

Suika's eyes widened beneath her glasses, basically sparkling with excitement. "R-really?! Th-then, detective Suika will be on call for you whenever necessary!" She did a cute little salute which quickly turned into a giggling fit, already much more comfortable with him. After all, her dear uncle gushed so much about his dear lover, it was like she already knew him.

"Well," Ryusui was obviously happy with how well they were getting along, ignoring the fact that he suddenly sprung an unknown child at him. "How about we eat dinner? I made a gorgeous meal for us." Picking his niece up once again, he grabbed his lover's hand and led him to the dining hall.

It was only because he was so forward that Senku could let himself be whisked away by this man, his confidence in knowing that he'd never know how things will go unless he tried. Somehow, it made his heart squeeze and the box in his pocket feel even heavier.

His niece was a naturally kind and sweet child, shy at first, but not afraid to make conversation once she was excited about something. It wasn't hard to get lost in all of her thoughts while happily munching on her chicken.

He felt a warm hand cover his, looking over to see Ryusui, but he was still paying attention to the girl. Still, he thumb drew circles against his skin, making him feel- butterflies. Seriously, after a year and he hadn't gotten over this?

Once they finished eating, they returned to the living room and sat around the tree. "Suika has to spend Christmas day with her family, so I hope you don't mind if we do this." He kissed Senku's cheek, rubbing his back to ease any possible anxiety he might be feeling. Of course, he was returned with being pushed away.

"Not in front of her, you perverted bastard."

The older let out a hearty laugh, apologizing to the girl who was sitting and waiting patiently, trying not to let her excitement show too much.

She was ecstatic as she opened her gifts, immediately putting on her detective hat and trying out her magnifying glass. Those were her favorites, despite getting some more expensive things, but she made sure to show her appreciation for each and every gift. Showing them off to her uncle, modeling and carefully putting them back in the box they came from.

It was sweet to watch, and a relief to know someone who seemed to care about her family so much could make him smile.

"Will I…be able to see uncle Senku more from now on?" She spoke up, as if she had been working up the courage to ask.

Heh, calling him 'uncle', even unknowingly, that was… "Yeah. Or else I'm gonna have a problem with  _ him _ ." He nudged Ryusui, who quickly took the hint.

"Yes, of course, that was the point of this, after all." He stood and helped Suika put all of her things inside a few bags so they would be easier to take home, the young scientist opting to not make it more complicated and just watched. Though it was unexpected, he truly didn't mind meeting her.

It just came off as...slowly introducing family to your lover, in hopes of them getting along. At first, he assumed it was for approval, but a grown man didn't need approval from his family. The only other reason he could think of was...to just be open about who he loved.

"Oh, looks like your mom is here." The blonde commented, hearing the knock on the door. He glanced over to his lover, eyes asking if he wanted to go out and meet her. After a quick shake of his head, he hoisted Suika up along with her bags. "Alright darling, say goodbye."

Her bottom lip sucked in a bit, waving her hand, disappointed that their already short time together was coming to an end. "Suika will start helping soon!" She called out as she was carried away. "BYEEE!"

Senku waved back, shaking his head. Good thing being friends with children was a science in of itself. She just made it real easy for him.

While they were gone, Senku took out the small black box in his pocket, opening it and looking at the two rings inside. One slightly bigger than the other. He was more than confident that the gift would be a hit, but for some reason, he still felt an annoying rise of anxiety creeping up his shoulders.

That sort of thing was probably normal, after all, this was his first relationship, as abnormal as it seemed from the outside.

He took out the ring that was his size and slipped it onto his finger, face flushing at the way it looked, and imagining them matching… Getting these really was worth it.

Once he could fear footsteps coming back, he snapped the box closed and stood, holding it behind him and acting casually. Which just made him look even more inconspicuous, but that was the point.

Ryusui entered the room, stopping when he saw his lover pretending to be coy. "Ah? What's this?" He walked over, hands cupping Senku's cheeks, squeezing them. "Do you perhaps have something for me?"

His red eyes squinted up at the man, sticking his tongue out. "I'm 10 billion percent not giving it to you if you don't stop. I'll make you want until tomorrow."

Immediately, the hands were gone, held up as if he were surrendering.

"Alright, I admit, I'm much too anxious to see what my little dove got me to play around."

Ryusui's smile softened, giving his small lover a wink.

God, it wasn't fair how he could make his heart skip a beat with something as small as that.

Senku waited a moment, shifting it in his hands and grinned and the other began tapping his foot. "Heh, fine." He brought the box to the front, keeping his eyes on the blonde as he slowly realized what it was, opening it while making sure the ring on his finger was also visible.

Ryusui's eyes were wide, lips parted as he looked down at the box, at the silver ring just for him. But he was… too quiet. For too long. The younger closed the box and raised an eyebrow, the anxiety slowly coming back. "What? You don't like it?"

No response right away, but then, a laugh. "Hah… I'm… Dove, no, of course I love it." He pinched the bridge of his nose, shaking his head. "I just can't believe you would have done something like that, and I…" He sighed and smiled. "Well, I guess now's a good time to give you my gift, too."

The man slowly lowered himself, getting on one knee- wait, no. This couldn't be what he thought it was. Until Ryusui looked up at him and brought out a small black box of his own, unveiling a small, silver ring just for him. Except this one had a small diamond in the middle.

"You…" Senku was nearly frozen, hand letting go of the box and turning into a fist to punch the other in the head with. Not with force or anything, just… "You idiot! What kind of person proposes after just a year!?"

And of course, the sailor just grinned and stood, taking Senku's hand and wrapping his arms around his waist. "Me, obviously."

He didn't step away, just grabbing his shirt and holding onto it, his scarlet eyes trying to find a reason why. "What if I were just after your money, huh? Are you really going to marry someone who could easily be taking advantage of you?"

"But you aren't."

The small claim made him suck in a breath.

"Senku, you're smarter than that." He brushed away one of his forelocks, hand cupping his cheek and forcing him to make eye contact. "You know that I already know you too well to ever believe that." He leaned closer, whispering into his ear. "I know you're working hard, submitting all you can to get into top colleges."

He dipped the younger further, completely supporting his body so he wouldn't fall to the ground.

"I've barely given you anything, yet you insist on paying me back one day. My love," His forehead rested on his shoulder. "You can reject it, but I'll ask you over and over as long as you're by my side."

Again, quiet filled the room. The only thing that could be heard was a heartbeat, and neither one could tell just whose it was.

A shaky breath leaving him, Senku wrapped his arms around the man and hugged him tightly. "You idiot… if it was anyone else, they'd be running away by now." 

"Heh, that's why I chose you."

The two inched closer, pressing their lips together and fully embracing the other. The way his mouth moved against his was more than enough to let him know just how serious he was about all of this.

The kiss ended too soon for Senku, opening his mouth to say something but was quickly cut off. "So? Do you accept?"

"Of course not."

Ryusui blinked.

"...Huh?"

Now it was Senku's time to grin. "Of course I'm not marrying you now. You have to wear the ring I got you for at least another year, asshole."

"What? But baby- we can refund them!"

"Nope." He reached down to grab the box, taking the ring out and sliding it onto the other's finger. "Good, it's a perfect fit." He snickered and kissed his hand, humming at the look of disappointment on his face. "Hey, don't give me a pity party. You know it won't work… Keep that same ring, try again and again until I say yes." He planted a quick kiss on his lips. "You said you'd do that anyway, right, or are you so quick to go back on your word?"

"So… does this mean we're engaged to be engaged?" Ryusui's face lit up as he spoke, the suggestion earning him another hit on the head. "Sorry, but I must ask…" He held his hand, intertwining their fingers together, admiring how the rings looked together. "May I take you to bed now? I've been dying to do it ever since I saw your wonderful gift."

Senku rolled his eyes, hanging his head back. "Yeah. Thought you'd never ask."

Immediately, he was scooped up, carried to the bedroom, his lips being catched by the other and refused to leave. Even happily welcoming the smooth glide of Ryusui's tongue into his mouth.

"Do you— mmf-" His back hit the bed, clothes already being pulled off by the other. "Did you get more of the stuff?"

An affirmative hum against his lips was the answer he got. The stuff in question being more lube, and of course he did, hand wandering to the nightstand and pulling out the pink tube.

Senku shivered as the air hit his body, becoming nude much more quickly than he thought he'd be. But he wouldn't let himself be like this alone, basically clawing the other's button-up off, placing his cold hand against his warm chest. His abs, firm and solid, made it easy to feel Ryusui up for almost hours on end.

"Mm? Aren't you gonna continue?" He murmurs, more than happy to stay together, kissing for hours. But with the fiery look in his beloved's eyes, he knew relaxing wasn't gonna be on the table tonight.

Hands adjust their grip around Senku's small waist, being yanked at the same time as Ryusui rolls his hips forward, earning him a rewarding moan slipping from the younger's mouth as their cock's slide up against one another. It's something he absolutely can't  _ stand _ , his legs already wrapping around Ryusui's waist and biting his lip, dick twitching and getting closer to fully hard with every grind of their hips.

Lips attached themselves to his neck, licking up and making sure Senku felt every mark he left on his pale skin.

His moans were quiet, savoring every time his cock head brushed up against his lover's in just the right spot, feeling a familiar hunger inside of him.

"Mmngh… Ryu… Enough…" His back arched, skin feeling as if it were burning at any contact, breath stuttering as he had to make it clear what he wanted. "Give it to me, please…"

Senku turned his head to get his attention, biting the man's cheek so he could _ get to it. _

Finally, he heard the lube bottle pop open, spreading his legs to give him easier access. It was routine, something they didn't need to make sure about.

A fingertip was pressed against his hole, rubbing circles around it before pressing inside, a relieved sigh leaving the boy.

If there was something Ryusui liked taking his time on, it was the preparation. Only adding another finger when Senku was squirming beneath him. Massaging his walls and teasing every inch he could reach.

There was no use in arguing, otherwise it'd take longer, just laying back and being grateful he was being touched in the first place.

If he just counted in his head and didn't think about just how badly he wanted the dick that would brush against his leg, it wasn't so bad. Before he got to 300, there were three thrusting in and out of him, forcing him to get out of his own head.

"Oh…  _ oh… _ " Senku kicked his hand away, flushed face glancing up to focused amber eyes. "Fuck me, you idiot…" 

Ryusui grinned, once again proud that he had driven someone so cocky to that point, even if his own cock was aching to be inside his beloved.

Cock finally was lined up with his ass, rubbing his length against it just to get a few more whines out of him before pressing into him, bucking his hips up and completely filling the pink void.

" _ Nngh! _ " Senku immediately cried out, legs tightening around his lover's waist as his walls twitched around the scorching hot length pulsing into him, practically begging to fuck him senseless. With half-lidded eyes and a small nod, he gave full permission for the man to do just that.

His hands twisted into the sheets, mouth open and letting every sweet sound spill out of his mouth as he was fucked into the bed, head back against the pillow.

As if he were invited, Ryusui leaned over and caught his lips in an open-mouthed kiss, swallowing each moan, mixing them with his own.

Hips slapped flush against his ass with every thrust, his cock reaching a spot deep inside of him, attacking his prostate along with every other possible erogenous zone.

But the kissing—  _ God _ , the kissing made him feel as if his head were in the clouds. Their tongues rubbed against each other, a sense of devouring that neither could explain. But it's all they could focus on, along with their lower bodies moving.

"Senku, shit, you feel so fucking perfect.." Ryusui's voice sounded lower than intended, muttering against his lips and almost growling, the sound of wet skin slapping against skin growing louder as his thrusts became more animalistic. "I love you, fuck, so fucking good…"

Hands traveled down his back, the caring touches so different than his pink void being abused, until the hands stopped on his ass, gripping it tightly and lifting it a bit, making it even easier to fuck him harder.

Senku's own dick was flailing helplessly, a string of pre-cum being left on his stomach, the desire in his lower stomach growing quickly. "Oh god- Ryusui, it's coming…" He gasped out, only being able to watch the huge length disappear inside him repeatedly. His fingertips brushed along his lower stomach, muddied scarlet eyes filled with desire gave away what he wanted.

And of course, who was Ryusui but a giving man? Kissing his lover once more, hooking a leg over his shoulder and bending him to his limits as he rolled his hips, biting Senku's bottom lip and fucked him like he deserved. Driving out every sound he could as he held onto his deliciously small waist, singing his own pleasure as his cock twitched inside of him.

A gasp left Senku- then a pause as he choked on a moan, eyes rolling up just a bit as his ass squeezed around Ryusui's cock, cum squirting against both of their stomachs in small bursts. But the best thing of it all was that Ryusui  _ didn't stop. _ Not until he was done. But with his ass sucking him in so tightly, it didn't take long for his hips to stutter, pressing himself as deep as possible as he kissed him, pouring his cum into the twitching hole.

The orgasm left Senku fuzzy, kissing his lover back lazily as he felt the hot liquid began to leak onto the bed as the length was pulled out.

"Mm… are you satisfied now?" He mumbled, head nuzzling into the pillow.

"Not at all." The blonde grinned and rubbed Senku's stomach, knowing just how tired he got after intense sessions like that. "You can sleep if you let me have fun."

"You damned perv…" He grabbed his hand, smiling at how their rings were shining together, fitting their skin so well. "You seriously are crazy for proposing to me… If it hadn't happened right in front of me I wouldn't believe it." 

Ryusui kissed Senku's knuckles. "What can I say? I'm seriously head over heels. I love you so much I don't know what to do with myself."

"Don't start with all this again-"

"I'm serious, Senku." His eyes changed a bit, more determined, bringing the other closer and kissing his forehead. "If there's ever even a sliver of doubt, I need to erase it. Do you know how I'm always saying I want everything?" He paused, wanting an actual answer.

"...Yes."

"Right now, you are my everything."

Senku groaned, rolling away from him. "Ugh, you're such a sap! I wish I only liked you for your money." He frowned, looking up and letting out a sigh. "You know I won't be saying anything like that to you, right? If you have any doubt, it's on you."

He plopped his chin onto his palm, looking away as his ears slowly turned red. "But,… you already know... I love you, so…"

Ryusui was absolutely beaming, his smile much too bright and his eyes filled with sparkles. "I hope I only have to wait a year for you to wear the ring I got you… Merry Christmas, Senku. I love you."

"...I know."

**Author's Note:**

> A gift for Ciel! I hope you enjoy! ❤️
> 
> Feel free to join the TKS discord! https://discord.gg/5nCtevKKyQ


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